Something I think could be really cool for MNK would be to merge its AoE combo with its ST combo for updated visuals and just have half your ST combo have fall-off damage that can be spammed for AoE instead of having your AoE combo be entirely divorced.

Bootshine upgrades to Shadow of the Destroyer
Twin Snakes upgrades to Four-Point Fury
Snap Punch could then be upgraded to a new third AoE in replacement of Rockbreaker and then True Strike can receive a new ST animation.
You'd need to make a couple tweaks to make the AoE half of your combo work the way it does currently, but otherwise, you'd get some more exciting animations for your combos while also trimming down on total buttons and thus giving MNK a ton of room to grow.